Dermatitis/Eczema

Question 1

What is Hyperkeratosis?

Answer 1

Increased thickness of keratin layer

Question 2

What is Parakeratosis?

Answer 2

Persistence of nuclei in the keratin layer

these would usually be lost in the cornification process in the granular layer

Question 3

What is Acanthosis?

Answer 3

Increased thickness of epidermis

Question 4

What two things can be seen histologically in a skin biopsy with eczema?

Answer 4

Inflammatory cell infiltrate

Spongiosis

Question 5

What is spongiosis?

Answer 5

Oedema between keratinocytes

Question 6

What are inflammatory cell infiltrates?

Answer 6

Acute or chronic

lymphocytes and/or neutrophils

Question 7

Describe the morphology of the acute phase of eczema

Answer 7

papulovesicular
erthematous (red) lesions
oedema (spongiosis)
ooze or scaling and crusting

Question 8

Describe the morphology of the chronic phase of eczema

Answer 8

thickening (lichenification)
elevated plaques
Increased scaling

Question 9

`What 4 concepts are the best descriptors of eczema?

Answer 9

Itchy
ill-defined
erythematous
scaly

Question 10

Describe the pathogenesis and histological appearance of a Contact Allergic Dermatitis

Answer 10

PATHOGENESIS: Type IV delayed hypersensitivity reaction

HISTOLOGY: spongiotic dermatitis

Question 11

Describe the pathogenesis and histological appearance of a Contact Irritant Dermatitis

Answer 11

PATHOGENESIS: Trauma e.g. Soap/water

HISTOLOGY: spongiotic dermatitis

Question 12

Describe the pathogenesis and histological appearance of Atopic eczema

Answer 12

PATHOGENESIS: Genetic and Environmental factors = inflammation

HISTOLOGY: spongiotic dermatitis

Question 13

Describe the pathogenesis and histological appearance of Drug related eczema

Answer 13

PATHOGENESIS: Type I and Type IV Hypersensitivity Reaction

HISTOLOGY: Spongiotic dermatitis and Eosinophils

Question 14

Describe the pathogenesis and histological appearance of photo-induced/photosensitive eczema

Answer 14

PATHOGENESIS: Reaction to UV light

HISTOLOGY: spongiotic dermatitis

Question 15

Describe the pathogenesis and histological appearance of Lichen Simplex

Answer 15

PATHOGENESIS: Physical Trauma to skin e.g. scratching

HISTOLOGY: spongiotic dermatitis and external trauma

Question 16

Describe the pathogenesis and histological appearance of Stasis Dermatitis

Answer 16

PATHOGENESIS: Physical Trauma to skin e.g. hydrostatic pressure

HISTOLOGY: spongiotic dermatitis and extravasation of RBC’s

Question 17

What are the most common causes of contact allergic dermatitis?

Answer 17

chemicals
topical therapies
NICKEL
plants

Question 18

Describe the process of patch testing for a specific allergen

Answer 18

Batteries of allergens are placed in small wells
Applied to back skin
Left in place for 48 hours
Reactions checked at 96 hours

Question 19

What is a contact irritant dermatitis?

Answer 19

Non-specific physical irritation rather than a specific allergic reaction

Eg Soap/detergent/cleaning products, water, oil

Question 20

Name clinical features which are often seen in hand dermatitis

Answer 20

Erythema
scaling
fissuring
lichenification
nail dystrophy
crusting

Question 21

What type of dermatitis is Nappy Rash?

Answer 21

irritant contact dermatitis to urine

sometimes with ulceration

NOTE: sparing of flexures - unlike in fungal infection

Question 22

What percentage of school children are affected by atopic eczema?

Answer 22

25%

Question 23

How can pruritus in atopic eczema affect children of school age?

Answer 23

Leads to sleep disturbance and therefore neurocognitive impairment at school

Question 24

Describe the typical distribution seen in atopic eczema

Answer 24

Flexural distribution

(inside elbow, back of knee, inside of wrists, front of ankles)

sometimes eyes/neck/genital areas

Question 25

What other atopic diseases are often associated with eczema?

Answer 25

hayfever asthma food allergy

Question 26

Describe the appearance of atopic eczema in skin of colour

Answer 26

papular ill defined erythema (often difficult to see) scaling extensive lichenification and keloid scarring

Question 27

What secondary infection is common in atopic eczema

Answer 27

staph aureus **gold crusting** (this easily multiplies on eczema prone skin)

Question 28

What variation of eczema presents as monomorphic punched out lesions and what virus is it caused by?

Answer 28

Eczema Herpeticum Caused by Herpes Simplex

Question 29

What is the diagnostic criteria for atopic eczema in the UK?

Answer 29

Itching plus 3 or more: - Visible (or Hx of) flexural rash - Personal history of atopy (or 1st degree relative if under 4) - Generally dry skin - Onset before age 2 years

Question 30

Describe the progression of treatments for eczema

Answer 30

- Plenty of emollients - Avoid irritants including shower gels and soaps - Topical steroids - Treat infection - Phototherapy – mainly UVB - Systemic immunosuppressants - Biologic agents

Question 31

How does discoid eczema usually present?

Answer 31

Well defined discrete lesions Patient can often be atopic too Also can cause secondary infection

Question 32

How is photosensitive eczema usually noticed?

Answer 32

Cut off at collar **also known as Chronic Actinic Dermatitis**

Question 33

Where does stasis eczema usually present?

Answer 33

The lateral malleolus

Question 34

What is another word for seborrhoeic dermatitis?

Answer 34

Cradle Cap

Question 35

What is seborrhoeic dermatitis usually accompanied by?

Answer 35

Fungal infection

Question 36

What is typical of Pompholyx Eczema?

Answer 36

Sudden onset of Spongiotic vesicles | On lateral aspect of the digits